The worst thing to happen was to upgrade my 3G to iOS 4.x ! It has been so slow and reboots itself, sometimes completely ignores requests to open apps. Apple's cure: delete all your apps or buy a iPhone4. No thanks.

iOS 4.2.1 works a lot more efficiently than iOS 4.0 and 4.1! I reluctantly updated as i am unlocked.. i therefore lost the unlock, but i re-unlocked using the iPad baseband (6.15.00). SO if you are having performance issues with iOS 4.0 or 4.1 on the 3g, i say upgrade to 4.2.1, works a lot better!